Industrial polyurethane elastomers are based on polyurethane prepolymers made by reacting polyols with excess molar amounts of diisocyanate monomers. Polyester polyols are widely used due to ease of production and relatively low production costs. Polyurethane elastomers made from polyols, such as polyester polyols and polycarbonate polyols, have high crystallinity or melting points and tend to build up crystallinity or become harder over extended periods of time. This is especially true at temperatures less than 20° C. In other words, elastomers derived from polyester polyols become harder over extended time periods, and especially become harder at low temperatures. For applications requiring uniform performance properties and reduced environmental sensitivity, changes in properties such as hardness, crystallinity, hydrolytic stability, or environmental stability, are not desired. For example, environmental stability is especially important for polyurethane printing rolls since they require consistent and good printing performance over a wide range of temperatures and humidities.
Thus, the need exists for polyurethane elastomers that possess good environmental stability, especially at low temperatures, and for processes for making such polyurethane elastomers.